The finely dissected leaves, dark petioles, creeping stems, smaller spores, and terrestrial habit distinguish Cystopteris reevesiana from C . fragilis in the southwest. On rock and at high elevations, however, C . reevesiana can have stems with short internodes and leaves that are reduced in size and dissection (resembling C . fragilis ). In southern Colorado, the two species are sympatric in some areas and form triploid hybrids. Cystopteris reevesiana and C . bulbifera are the diploid progenitors of C . utahensis , which occasionally crosses with C . reevesiana to produce sterile triploid hybrids of intermediate morphology.